scripted-diff: Use the C++11 keyword nullptr to denote the pointer literal instead of the macro NULL

-BEGIN VERIFY SCRIPT-
sed -i 's/\<NULL\>/nullptr/g' src/*.cpp src/*.h src/*/*.cpp src/*/*.h src/qt/*/*.cpp src/qt/*/*.h src/wallet/*/*.cpp src/wallet/*/*.h src/support/allocators/*.h
sed -i 's/Prefer nullptr, otherwise SAFECOOKIE./Prefer NULL, otherwise SAFECOOKIE./g' src/torcontrol.cpp
sed -i 's/tor: Using nullptr authentication/tor: Using NULL authentication/g' src/torcontrol.cpp
sed -i 's/METHODS=nullptr/METHODS=NULL/g' src/test/torcontrol_tests.cpp src/torcontrol.cpp
sed -i 's/nullptr certificates/NULL certificates/g' src/qt/paymentserver.cpp
sed -i 's/"nullptr"/"NULL"/g' src/torcontrol.cpp src/test/torcontrol_tests.cpp
-END VERIFY SCRIPT-

src/test/pow_tests.cpp

@@ -66,7 +66,7 @@ BOOST_AUTO_TEST_CASE(GetBlockProofEquivalentTime_test)
     const auto chainParams = CreateChainParams(CBaseChainParams::MAIN);
     std::vector<CBlockIndex> blocks(10000);
     for (int i = 0; i < 10000; i++) {
-        blocks[i].pprev = i ? &blocks[i - 1] : NULL;
+        blocks[i].pprev = i ? &blocks[i - 1] : nullptr;
         blocks[i].nHeight = i;
         blocks[i].nTime = 1269211443 + i * chainParams->GetConsensus().nPowTargetSpacing;
         blocks[i].nBits = 0x207fffff; /* target 0x7fffff000... */